Many buildings include multiple roof sections that are at angles with respect to each other and that intersect. The joint at which two roof sections intersect at a peak or point is often referred to as the roof “ridge.” The concave joint between two roof sections is often referred to as a valley. Roof valleys typically encounter high water loads because the valley collects water running off of two roof sections.
The roof sections are typically covered by a plurality of shingles, and on many roofs, a valley flashing component is installed at the valley joint where the use of shingles is not a practical option. The valley flashing runs along the valley joint and shingles are layered on top of it. The purpose of the valley flashing is to provide increased protection against water infiltration at the valley joint. Without proper sealing of the valley joint, water can seep underneath the roof shingles and cause rot and deterioration of the roof decking and rafters.
Traditional valley flashing designs suffer from notable drawbacks. First, in geographical areas in which stormy, windy weather is common, water can be forced far enough under the shingles that are layered over the edge of the valley flashing and can then reach the roof material under the shingles and flashing. High winds, which are often accompanied by rain, can lift parts of the shingles and allow blown rain to move between the shingles and the flashing.
Next, valley flashing is often made of metal, which can act as a lightning rod. The metal valley flashing can attract lightning, which, when it occurs, can destroy the structure to which the flashing is attached. Metal flashing also presents difficulties in joining multiple pieces to cover a long valley joint. Joining a number of individual flashing components together to cover a valley joint are typically requires sealing with caulk, for example, silicone caulk. Caulked joint seals have a limited lifespan before they degrade and cause the seal to fail. Seal failure requires expensive repair or it can cause water leaks and, eventually, rot.
Traditional valley flashing is typically installed by applying a fastener, such as a nail, directly through the flashing itself and into the roof decking. This has some notable disadvantages. First, it creates an opening through the flashing through which water can reach the roof decking. Second, it eliminates the ability of the installer to make adjustments to the positioning of the flashing as he or she is installing the shingles over the edge of the flashing.
Accordingly, what is desired is valley flashing that provides improved protection of a roof valley joint from water intrusion, particularly in geographical areas subject to intense storms. Further, what is desired is a valley flashing that is resistant to degradation over time. Even further, what is desired is a valley flashing that is easier and less cost intensive to manufacture, install, and maintain.